read / write / close sync for device files

[Amit Nagal]

Hi ,

if  a application is  doing read /write I/O with a  usb device ,  in 2
different threads in userspace ,

and at usb disconnect event ,  read thread returns with error and
application calls close() subsequently without waiting for write
thread to finish .

Do  the VFS upper layers  maintain locks that  take care that until
both read and write methods in usb driver donot finish and return with
error in kernel space

close will pend and usb driver release method will not be called ?

Regards
Amit Nagal